CN107003423B

CN107003423B - Marine cable installation suitable for preventing pollution

Info

Publication number: CN107003423B
Application number: CN201580068981.6A
Authority: CN
Inventors: R.B.希伊特布林克; B.A.萨特斯
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2014-12-16
Filing date: 2015-12-14
Publication date: 2021-04-16
Anticipated expiration: 2035-12-14
Also published as: CN107003423A; ES2882953T3; BR112017012447A2; WO2016096770A1; KR20170095984A; US20170336530A1; RU2695939C2; JP2018509886A; RU2017125001A3; EP3234653B1; US11137518B2; US10557968B2; DK3234653T3; US20200142093A1; RU2017125001A; EP3234653A1; JP6328344B2; KR102561246B1

Abstract

The present invention provides a marine cable device configured for preventing or reducing bio-fouling along its outer surface, which is at least temporarily exposed to water during use. The marine cable device according to the invention comprises at least one light source configured to generate an anti-fouling light and at least one optical medium configured to receive at least a part of the anti-fouling light. The optical medium includes at least one emitting surface configured to provide at least a portion of the anti-fouling light on at least a portion of the outer surface.

Description

Marine cable installation suitable for preventing pollution

Technical Field

The present disclosure relates to a marine cable device adapted to prevent pollution, which is commonly referred to as anti-fouling. In particular, the present disclosure relates to the anti-fouling of submarine cables such as umbilicals or seismic streamers.

Background

Biological contamination or biological contamination is the accumulation of microorganisms, plants, algae, and/or animals on a surface. The variety of biofouling organisms is highly diverse and extends far beyond the attachment of barnacles and seaweeds. According to some estimates, over 1800 species, including over 4000 organisms, are responsible for biological contamination. Biofouling is divided into microbial fouling (microfoulding) which includes biofilm formation and bacterial adhesion, and large area biofouling (macrofouling) which is the attachment of larger organisms. Organisms are also classified as hard or soft fouling types due to different chemistries and biology that determine what prevents them from settling. Calcareous (hard) contaminating organisms include barnacles, encrusting bryozoans, mollusks, polychaetes and other duct worms, and zebra mussels. Examples of non-calcareous (soft) contaminating organisms are seaweed, hydroids, algae and biofilm "slime". Together, these organisms form a polluting community.

In several cases, biological contamination poses a number of problems. The machine stops working, the water inlet is blocked and the heat exchanger suffers from reduced performance. Thus, the subject of anti-fouling (i.e., a process that removes or prevents the formation of biological contamination) is well known. In industrial processes, bio-dispersants can be used to control bio-contamination. In a less controlled environment, organisms are killed or repelled using a coating, heat treatment or energy pulse using biocides. Alternatively, mechanical structures have been developed for removing contamination that has formed on a particular structure.

Several marine cable devices are used in mobile and or fixed marine structures. A subsea umbilical is one of these marine cable installations deployed on the seabed (ocean floor) to supply necessary controls, energy (electrical, hydraulic) and chemicals to subsea oil and gas wells, subsea manifolds and any subsea systems that require remote control, such as remotely operated vehicles. Subsea intervention umbilicals are also used for offshore drilling and workover activities. The amount of umbilical changes as the contamination begins to grow. This results in additional load to all mooring elements. This becomes even worse if the frequency of vibration of the system is synchronized with the frequency of the waves in the water. Thus, contamination on the outer surface of the umbilical is undesirable.

Another area in which marine cable equipment is often used is marine seismic surveying. Marine seismic surveys are typically performed using cables towed near the surface of a body of water. The marine cable devices in this case are commonly referred to as "streamers," which in the most general sense are marine cable devices towed by a seismic vessel. The cable has a plurality of seismic sensors disposed thereon at spaced apart locations along the length of the cable in this embodiment. The seismic sensors are typically hydrophones, but may be any type of sensor that responds to pressure in the water or to changes therein with respect to time. Typical marine seismic cable installations may be up to several kilometers in length and may include thousands of individual seismic sensors. The build-up of contamination on the cable can interfere with signal transmission fidelity and increase cable drag.

Anti-fouling arrangements for such marine cable devices are known in the art. US2011197919 and JP2012040538 relate to mechanical anti-fouling systems for marine cable installations.

Disclosure of Invention

Biological contamination on the outer surface of marine cable equipment causes serious problems. The main problem is the change of the properties of the cable, such as its quality or noise level, etc. This results in the cable not being able to provide its function as designed or in further physical phenomena that cause problems for the cable or the entire structure to which it is attached.

There are many organisms that contribute to biological contamination. This includes very small organisms such as bacteria and algae, but also very large organisms such as crustaceans. The environment, water temperature and purpose of the system all play a role here. The environment of the box cooler is ideally suited for biological contamination: the cooled liquid is heated to a moderate temperature and a constant flow of water brings nutrients and new biomass.

Accordingly, a method and apparatus for preventing fouling is necessary. However, prior art systems are inefficient in their use, require periodic maintenance, and are expensive to implement. It is therefore an aspect of the present invention to provide a marine cable installation with an alternative anti-fouling system according to the appended independent claims. The dependent claims define advantageous embodiments.

Therewith, a method is presented based on an optical method, in particular using ultraviolet light (UV). It appears that most microorganisms are killed, rendered inactive or unable to reproduce with 'sufficient' UV light. This effect is mainly governed by the total dose of UV light. A typical dose of 90% for killing a particular microorganism is 10 milliwatt-hours per square meter.

The marine cable apparatus according to the present invention may supply and/or transmit at least one of data, electricity, water, gas or oil to or from the seabed. Alternatively, it may also carry at least one or more sensors, optical and/or electrical devices along the outer surface. In this sense, any and all submarine cable-like structures are within the scope of the present invention. Such cable devices may be used in vessels, fixed marine structures, offshore structures or seismic survey structures.

The marine cable device according to the invention is configured for preventing or reducing bio-fouling along its outer surface, which is at least temporarily exposed to water during use. The marine cable device comprises at least one optical medium configured to receive at least a portion of the anti-fouling light generated by at least one light source, the optical medium comprising at least one emitting surface configured to provide at least a portion of the anti-fouling light on at least a portion of the outer surface.

In a particular embodiment, the marine cable device further comprises the at least one light source configured to generate anti-fouling light to be received by the optical medium.

In one embodiment, the marine cable device, the anti-fouling light emitted by the light source is in the UV or blue wavelength range from about 220nm to about 420nm, preferably about 260 nm. Suitable levels of anti-fouling are achieved by UV or blue light from about 220nm to about 420nm (particularly at wavelengths shorter than about 300 nm), for example from about 240nm to about 280nm (which corresponds to the light known as UV-C). 5-10 mW/m can be used²Antifouling light intensity in the range of (milliwatts per square meter). Alternatively, a combination of UV-A and UV-C light may be used. It is clear that higher doses of anti-fouling light will achieve the same result, if not better.

In one version of the above-described embodiment in which UVA light is used as the anti-soiling light, the exterior of the optical media is coated with TiO2, since TiO2 is a physical sunscreen to protect against UVA.

In one embodiment of the marine cable device, the light source is a laser and the at least one optical medium is in the form of a transparent optical fiber fed by the laser light source. The laser light source is preferably positioned close to the end of the optical fibre that is located outside the water and is arranged to provide anti-fouling light from that end. The optical fiber guides the anti-fouling light through its length and provides the anti-fouling light on the exterior of the cable over which it is coupled. Accordingly, contamination of the outer surface on which the anti-fouling light is provided is prevented or reduced.

In an embodiment of the marine cable device, the optical medium is made of quartz and/or glass. Obviously, alternative forms of plastic may also be used for producing the optical medium. The optical media is preferably extruded from these materials in the shape of a semi-flexible rod.

In an embodiment of the marine cable device, a plurality of emitting surfaces is arranged on the optical medium. Accordingly, the anti-fouling light is outcoupled (out-coupled) onto the outer surface of the cable in a uniform manner and, thus, effective anti-fouling is achieved throughout a desired length of the cable.

In one embodiment of the marine cable device, more than one optical medium is provided in the form of optical fibers along at least a portion of the length of the marine cable device. Such an embodiment is suitable, for example, to ensure that a sufficient dose of anti-fouling light is provided on the outer surface of the marine cable device if necessary to provide redundancy for the anti-fouling light. In a version of this embodiment, the optical media may be provided with different refractive indices and/or wavelengths. Alternatively, the light source providing anti-fouling light to each optical medium may provide light at a different wavelength. Accordingly, antifouling lights of different colors can be provided simultaneously. Alternatively, multiple optical media may also be used to provide both UVA and UVC simultaneously in order to achieve a desired level of UV dose for optimal anti-fouling efficiency.

The amount of biocide needed can also be readily achieved with existing low cost, low power UV LEDs. LEDs may generally be included in relatively small packages and consume less power than other types of light sources. LEDs can be manufactured to emit (UV) light at various desired wavelengths, and their operating parameters (most notably, output power) can be highly controlled. Accordingly, in another embodiment of the marine cable device, an array of light sources in the form of light emitting diodes is used.

In a version of this embodiment, the array of LED light sources is preferably embedded in an optical medium, which is a UV transparent silicone composition in the form of a film, and the film is then applied on the outer surface of the cable so as to provide an anti-fouling light on the outside. In this embodiment, the distance between the LEDs should be determined based on the absorption of the UV light and the opening angle (opening angle).

In an alternative embodiment it is also possible that the optical medium in the form of optical fibers is embedded in a further optical medium, which is a UV transparent silicone layer. In this embodiment, the second optical medium in the form of a silicone layer further directs the anti-fouling light from the first optical medium in the form of the optical fiber to a region of the outer surface of the cable.

In an alternative embodiment of the invention, the optical medium in which the light source or another optical medium is embedded may be a sandwich of different types of materials, such as clear silicone in the middle and a tougher but more absorbing silicone layer on the outside. Another possibility is to add an air fence, wherein a small space tube is included in the layer. Alternatively, quartz may be used instead of air.

In a preferred embodiment of the marine cable device, the optical medium is wrapped around the outer surface of the cable. Accordingly, the anti-fouling light is provided on the outer surface of the cable in a uniform manner, and easy installation is achieved.

In one version of the embodiment described above, the optical medium is wrapped at a variable pitch along at least a portion of the length of the marine cable device, the optical medium being arranged such that the helix angle is smaller in areas with greater risk of contamination. For example, the helix angle may decrease as the cable moves deeper in the water, as the intensity of the directed light will decrease depending on the distance traveled. Accordingly, a uniform distribution of the anti-fouling light may be achieved throughout the length. On the other hand, as the optical medium reaches even deeper in water, the environmental properties in the sea change in such a way that: after a certain depth, less contamination is expected. In this case, the helix angle is then increased after a certain depth in order to optimize the relation between the anti-fouling light provided on the outer surface and the fouling level.

In an alternative embodiment, the optical medium is arranged on the outer surface of the cable longitudinally in a line parallel to the cable core. Accordingly, ease of manufacturing will be achieved, wherein the core, outer surface and the optical medium will be assembled together before the final package is completed.

In one embodiment, the marine cable device comprises a reflective layer between the optical medium and the cable in order to reduce the amount of anti-fouling light absorbed by the outer surface and to direct more anti-fouling light to a possible fouling area.

In one embodiment, the marine cable device comprises at least one spacer between the reflective layer and the outer surface. Accordingly, a small layer of air or water is created to increase efficiency, as both water and air absorb less UVC.

In one embodiment, the marine cable arrangement comprises means for harvesting energy for powering the light source. Accordingly, the need for an external power source is minimized and the cost efficiency of the system is improved.

In one version of the above embodiment, the means for harvesting is a Peltier element. In this embodiment, the warm liquid rising up from the ocean floor and the corresponding temperature difference are used to harvest energy via the Peltier elements.

In an embodiment of the marine cable device the optical medium is coloured or comprises Fluor particles in order to create a yellow glow, since it is desirable for the entire subsea structure to have a yellow colour mainly due to increased underwater visibility.

In an embodiment of the marine cable device, the optical medium may also have small side branches, where some light leaks into them. Accordingly, the anti-fouling light is better distributed over the entire area of the outer surface of the cable.

The outer surface of the cable may be covered in segmented segments, each segment having a separate anti-fouling light source. For example, an optical medium in the form of an optical fiber may be directed down to the desired depth/length of the cable and from there start a helical rotation. The anti-fouling light source may thus remain placed above the water line.

The term "comprising" is also included in embodiments in which the term "comprising" means "consisting of … …. The term "comprising" may mean "consisting of … …" in one embodiment, but may also mean "comprising at least the defined species, and optionally one or more other species" in another embodiment.

It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The invention further applies to a device comprising one or more of the characterising features described in the present description and/or shown in the attached drawings.

The various aspects discussed in this patent may be combined to provide additional advantages. Furthermore, some of the features may form the basis of one or more divisional applications.

Drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

FIG. 1 is a schematic representation of one embodiment of a marine cable apparatus;

FIG. 2 is a schematic representation of another embodiment of a marine cable apparatus;

FIG. 3 is a schematic representation of one embodiment of a marine cable device in which the optical media is wrapped at variable intervals along the outer surface;

FIG. 4 is a schematic representation of one embodiment of a marine cable installation in which multiple optical media in the form of optical fibers are used; and

FIG. 5 is a schematic representation of one embodiment of a marine cable apparatus including a spacer.

The drawings are not necessarily to scale.

Detailed Description

While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the present disclosure is not limited to the disclosed embodiments. It should be further noted that the drawings are schematic, not necessarily to scale, and that details that are not necessary for an understanding of the invention may have been omitted. Unless otherwise indicated, the terms "inner," "outer," "along," "longitudinal," "bottom," and the like, refer to the embodiments as oriented in the drawings. Further, elements that are at least substantially identical or that perform at least substantially the same function are denoted by the same numerals.

Fig. 1 shows as an embodiment a schematic view of a marine cable device (1) configured for preventing or reducing bio fouling along its outer surface (1200), the outer surface (1200) being at least temporarily exposed to water during use. In this embodiment, the marine cable device (1) further comprises at least one light source (2) configured to generate the anti-fouling light (211) and at least one optical medium (220) configured to receive at least a part of the anti-fouling light (211), the optical medium (220) comprising at least one emitting surface configured to provide at least a part of the anti-fouling light (211) on at least a part of the outer surface (1200). In this embodiment, the light source (2) is a laser and one optical medium (220) is in the form of a UV transparent fiber fed by said laser light source (2). In this embodiment, the optical medium (220) is wrapped along the outer surface (1200). The marine cable device (1) according to this embodiment comprises a further optical medium (225) in the form of a UV transparent silicone layer within which the first optical medium (220) in the form of UV transparent optical fibres is embedded. Further, in this embodiment, the marine cable device (1) comprises a reflective layer (230) between the optical medium (220) and the outer surface (1200).

Fig. 2 shows an alternative embodiment comprising an array of light sources (2) in the form of Light Emitting Diodes (LEDs). The optical medium (225) is a UV transparent silicone layer in which the LED light sources (2) are embedded. In this particular embodiment, the optical medium (225) is in the form of a long narrow strip, and the light sources (2) are alternatively positioned at the top and bottom sides of the strip to provide light along the gull length of the optical medium (225) with an optimal number of light sources (2). Further, in this embodiment, the marine cable device (1) further comprises a reflective layer (230) between the optical medium (220) and the outer surface (1200).

Fig. 3 shows a further embodiment of the marine cable device (1), wherein the optical medium (220) is wrapped along at least a part of the length of the marine cable device (1) with a variable pitch, the optical medium (220) being arranged such that the helix angle is smaller in areas with a greater risk of contamination.

Fig. 4 shows an alternative embodiment of the marine cable device (1), the marine cable device (1) comprising more than one optical medium (220, 222) in the form of optical fibers along at least a part of the length of the marine cable device (1). In this embodiment, the optical media (220, 222) have different refractive indices and/or wavelengths.

Fig. 5 shows an alternative embodiment of the marine cable device (1), the marine cable device (1) comprising more than one spacer (240) between the reflective layer (230) and the outer surface (1200). The plurality of spacers (240) are arranged in an organized manner so as to provide a uniform layer of air or water between the reflective layer (230) and the outer surface (1200), and thus less of the anti-fouling light (211) is absorbed, and correspondingly more of the anti-fouling light is provided on the area with contamination.

Elements and aspects discussed for or with respect to a particular embodiment may be suitably combined with elements and aspects of other embodiments, unless explicitly stated otherwise. The invention has been described with reference to the preferred embodiments. Modifications and alterations may occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof. Since contamination can also occur in rivers or lakes or any other areas in which the cooling device is in contact with water, the invention is generally applicable to cooling by means of water.

Claims

1. A marine cable device (1) configured for preventing or reducing bio fouling along its outer surface (1200), which outer surface is at least temporarily exposed to water during use, the marine cable device (1) comprising at least one optical medium (220) configured to receive at least part of an anti-fouling light (211) generated by at least one light source (2), the anti-fouling light being in the UV or blue wavelength range from 220nm to 420nm, the optical medium (220) comprising at least one emitting surface configured to provide at least part of the anti-fouling light (211) on at least part of the outer surface (1200); wherein the optical medium (220) is wrapped along at least a portion of the outer surface (1200).

2. A marine cable device (1) according to claim 1, further comprising at least one light source (2) configured to generate the anti-fouling light (211) to be received by the at least one optical medium (220).

3. A marine cable device (1) according to any one of the preceding claims, wherein the anti-fouling light (211) comprises one or more of UV-a and UV-C light.

4. A marine cable device (1) according to claim 1 or 2, wherein the light source (2) is a laser and the at least one optical medium (220) is in the form of a UV transparent fibre fed by the laser light source (2).

5. A marine cable device (1) according to claim 1 or 2 wherein a plurality of emitting surfaces are arranged to provide uniform out-coupling.

6. A marine cable device (1) according to claim 1 or 2, comprising more than one optical medium (220, 222) in the form of optical fibres along at least a part of the length of the marine cable device (1).

7. A marine cable device (1) according to claim 6 wherein the optical media (220, 222) have different refractive indices and/or wavelengths or the light sources (2, 22) provide anti-fouling light (211) to the optical media (220, 222) at different wavelengths.

8. A marine cable device (1) according to claim 1 or 2, comprising an array of light sources (2) in the form of light emitting diodes.

9. A marine cable device (1) according to claim 1 or 2, wherein the optical medium is a UV transparent silicone layer within which the light source (2) and/or a further optical medium is embedded.

10. A marine cable device (1) according to claim 1 or 2 wherein the optical medium (220) is wrapped along an outer surface (1200).

11. A marine cable device (1) according to claim 9 wherein the optical medium (220) is wrapped at a variable pitch along at least a part of the length of the marine cable device (1), the optical medium (220) being arranged such that the helix angle is smaller in areas with a greater risk of contamination.

12. A marine cable device (1) according to claim 1 or 2, comprising a reflective layer (230) between the optical medium (220) and the outer surface (1200).

13. A marine cable device (1) according to claim 12, comprising at least one spacer (240) between the reflective layer (230) and the outer surface (1200).

14. A marine cable device (1) according to claim 1 or 2, wherein the marine cable device (1) supplies and/or transmits at least one of data, electricity, water, gas or oil, or carries at least one or more sensors, optical and/or electrical devices along the outer surface (1200).

15. A marine cable arrangement (1) according to claim 1 or 2, wherein the marine cable arrangement (1) is used in a structure selected from the group consisting of a vessel, a fixed marine structure, an offshore structure and a seismic survey structure.